This application claims the priorities of German Application Nos. 100 18 222.4, filed Apr. 12, 2000 and 100 38 561.3, filed Aug. 3, 2000, the disclosures of which are expressly incorporated by reference herein.
The invention relates to an illuminator, in particular for a signal lamp such as for a motor vehicle.
Various illuminators which use light emitting diodes (LEDs) as a source of illumination have already become known. Such an illuminator is described, for example, in the German Utility Model DE 298 06 589. The illuminator, further described herein as a xe2x80x9cluminous meansxe2x80x9d in accordance with the prior art has a T-shaped printed circuit board which extends with the narrower, lower part into the base of the luminaire, where the electric connections leading to the outside are undertaken. A plurality of light emitting diodes are mounted in the upper, wider part of the printed circuit board.
By contrast, it is the object of the invention to propose a luminous means which exhibits a lower outlay of production and can, in particular, be constructed in a cost effective manner in high volume numbers.
This object is achieved by an illuminator, in particular for a signal lamp, having at least one LED, which is mounted on an LED printed circuit board, and having a base. A base housing is produced from plastic, and the base housing is penetrated by at least two contact elements.
Advantageous designs and developments of the invention are possible by means of the features described herein.
Accordingly, a luminous means according to the invention is provided with a base housing made from plastic. In addition to the more cost-effective production in large piece numbers, a plastic housing offers the advantage of electric and thermal insulation.
In this case, contact is made with the printed circuit board by virtue of the fact that at least two contact elements are provided which penetrate the housing of the base. Despite the insulating property of the base housing, current can be applied to the luminous means with the aid of the contact elements.
The contact elements are preferably arranged such that they penetrate a bottom plate of the base housing. It is possible thereby to fashion a base which can be inserted into standard holders and closes the required contact at the conventional contact points upon being plugged into the appropriate holder. The contact elements can, for example, be constructed in this case as contact pins which not only produce the external contact, but simultaneously project into the interior of the base as far as the components with which contact is to be made.
In a preferred embodiment of the invention, the contact elements are simultaneously provided with cutting and/or latching elements which serve the purpose of fixation in the base. By way of example, the cutting elements can be constructed in the form of, for example, sawtooth external teeth on the contact pins which cut into the base material upon being pressed in and thus mesh at least partially with the base plate, thus fixing the contact elements after they are pressed in. Latching elements with the aid of which the contact elements are latched on the base would also be conceivable in another embodiment.
In a particular embodiment of the invention, a base plate which is essentially transverse to the LED printed circuit board is provided, being connected to contact elements of the base. Owing to this type of construction, the base can be of the same design up to the base plate in each case for luminous means of different sizes.
Depending on the shape desired, the LED printed circuit board need only be used in a fashion appropriately modified in terms of size and shape.
A base for a luminous means according to the invention can be mounted with particular ease especially when use is made of a printed circuit board, fitted with said electronic components, as a base plate in conjunction with pin-shaped contact elements. All that is required in this case to finish the base unit is for the contact pins to be plugged in from the underside and connected to the base plate, which is put on from the top side of the base.
The connection of the contact pins to the base plate can be implemented in different ways. Thus, a plug-in, compression and/or soldered connection can be provided at this point. Preference is to be given in this case to solderless connections for the purpose of simplifying the mounting of the base according to the invention. Particularly in the case of a plug-in connection, this results in an extremely simple mounting of the cap by plugging together the three named different components, that is to say the contact pins of the base housing and the base plate.
In a development of the invention, this base with the essentially transverse printed circuit board can simultaneously contain electronic components such that the base constitutes a complete sub-assembly for a modular design of the luminous means. The components can be accommodated in this case either on the base plate or else also, without difficulty, in the base housing, because of the insulating property of the base housing. It is possible with the aid of such electronic components for the base to be configured as a complete connecting module for a multiplicity of different luminaires.
Thus, for example, the circuits required for supplying low-voltage power can be integrated into the base. Other functions, for example flashing functions, color selections or the like can also be accommodated in the base design according to the invention. If appropriate, when use is made of complex controls it is also possible for one or more control lines to be led outside from the base for the purpose of making contact.
The electronic components in the base housing or on the base plate can, for example, also contain electric circuits which enhance the interference immunity of the luminous means. Thus, for example, electromagnetic pulses, so-called surge and burst pulses which, for example can be produced by a lightening stroke or by power interruptions in the network, can be absorbed and ameliorated with the aid of such an electric circuit. This yields a substantially longer service life for a luminaire with luminous means according to the invention.
Moreover, if required it is possible straight away also to construct a plurality of LED printed circuit boards, for example in a triangular arrangement, for improved all around illumination on a base having said transverse base plate.
A base according to the invention is fitted with an LED printed circuit board in order to finish the luminous means. This printed circuit board is put on essentially transverse to the base plate, and contact is made with it. Various types of connections come into consideration, in turn, for making contact, for example a plug-in, compression or soldered connection. Solderless connections offer the advantage here, in turn, of simplified mounting.
Particularly in the case of a plug-in connection, the further construction of the luminous means according to the invention requires only that the desired LED printed circuit board be selected from a corresponding assortment and plugged on.
In a particular embodiment, fastening elements for further components are additionally integrally formed into the base housing. This can be done without difficulty chiefly by producing the base housing from plastic, and simplifies the mounting, for example of the base plate or of a cover on the base housing. All conceivable designs, for example a bayonet lock or threaded stub etc. come into consideration as fastening element in this case.
In a particularly advantageous embodiment, the fastening elements, for example for fixing the base plate or a spherical cap, are constructed as a latching element, and so the appropriate component can be mounted in a particularly simple and, if appropriate, redetachable fashion.
When the base plate is pressed into such latching elements, for example in the case of a plug-in connection, it is possible at the same time for contact to be made and for the base plate to be fixed with reference to the base housing.
In a development of the invention, there is provided as a cover a transparent spherical cap which surrounds the LED printed circuit board or LED printed circuit boards and is connected to the base element. The closure with the base can be constructed variously to be detachable or nondetachable. Thus, for example, the spherical cap can be bonded or welded to the base. Depending on the intended use, detachable connections, for example a latching or bayonet lock can also be conceived straight away.
The spherical cap can have a smooth outer surface, but in a particular embodiment it is also provided with light-guiding elements, for example lens profiles. The emission characteristic of the luminous means can be influenced with the aid of such a spherical cap structure. Prismatic structures can also be provided in order to implement a desired emission characteristic.
In addition to the function regarding the emission characteristic of the luminous means, the spherical cap also fulfills a protective and insulating function. Thus, for example, the spherical cap protects the interior of the luminous means against soiling. Moreover, the spherical cap constitutes a shock-hazard protection, since it insulates both electrically and thermally.
This protective and insulation function can be further improved, if required, by a seal between the spherical cap and the base of the luminous means.
In a departure from the form of spherical cap specified above, in other designs the spherical cap can be smooth and/or grooved both outside and inside.
In a particular embodiment of the invention, guide and/or fixing elements are also provided for the LED printed circuit board. These can be provided, for example, in the base housing or also in the base plate. However, it is advantageous also to fit an appropriate fixing element in the spherical cap. Such a fixing element can be provided in the inside of the spherical cap on its top side, such that in combination with fastening on the base plate or the base there is a comparatively large guide length, and thus a stable fastening of the LED printed circuit board.
The contact pins which penetrate the base plate of the base can be constructed not only to be electrically conductive, but also to be thermally conductive, and thus to promote the dissipation of heat from the interior of the luminous means.
A complete luminaire can be produced in a particularly favorable way with the aid of a luminous means according to the invention in the embodiment with the spherical cap specified above. In this case, the production of a complete luminaire further requires only a holder for the insertion of the luminous means which has appropriate holding elements for fixing at the desired place of use for all desired types of mounting, for example for bottom mounting, angle mounting, central mounting etc. Such a holder can have, for example, an external thread for fastening in a machine housing, a stand or the like. Insertion of the luminous means into the corresponding holder, which can, for example, contain conventional cable clamps for an electric connection, therefore finishes off the complete luminaire without the need for a complicated luminaire housing for the insertion of a luminous means with an additional spherical cap.
In a particular embodiment, it is expedient to provide for such a complete luminaire a seal between the holder and the base of the luminous means, such that the electric contact points between the holder and the luminous means are protected against the intrusion of dust and/or water.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.